In line with the original proposal and work over the past year showing the effect of zinc content on the physical properties of dental amalgam alloys, the proposed work for the coming year will proceed along the following lines: 1. A SEM, STEM and X-ray diffraction study of the zinc-containing amalgams to locate the zinc and determine whether it is present as zinc or an alloy of zinc with one or more of the other metals present. 2. Quantitative analyses of the alloys treated with HF to determine whether the amount of fluoride retained by the alloy is related to the composition of the alloy. 3. Cooperative effort (contingent on funding) with department of dentistry to test zinc-containing, fluoride treated alloys clinically. 4. To investigate the possibilities of various methods of decreasing the silver content of dental amalgam alloys without harming the desired amalgam properties excessively.